What is the difference between magnetic and primary inductance?

Question

I try to calculate ramp compensation resistor (Rcomp) for flyback SMPS converter design. For this, I examined slope compensation section at page 15 in NCP1252 datasheet by OnSemi.
But, there is a parameter which I don't understand. Calculations are below as screenshot:

Mixed point !!!
Ns/Np = 0,085
Lout = 27µH
Lmag = 13mH (?) WHY?
As I know, L2 = L1 x (N2/N1)^2
So, Lout = Lmag x (0,085)^2 = 27µH   --> Lmag must be 3,7mH
But, Lmag = 13mH in NCP1252 datasheet
Are magnetic and primary inductance different each other?

Andy aka · Accepted Answer

Are magnetic and primary inductance different each other?

No, they are not different unless you want to take into account leakage inductance (2 to 5%). I think you are not understanding the type of circuit they refer to: -

Page 16 and 17 are referring to a 2 switch−Forward Power supply specification and they use an extra inductor in the output circuit seen as L1 in the above schematic. That will be the 27 uH they refer to: -

What is the difference between magnetic and primary inductance?

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